The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton (1642–1727), using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting telescope. The Newtonian telescope's simple design has made it very popular with amateur telescope makers.
I think this is the appropriate subforum.
I'm curious as to what approaches have been taken. I know this prediction isn't correct. I can think of at least a couple ways that I could go about this. They may or may not give the same prediction.
One approach would be to simply use kinematics, and...
Hello, I am attempting to work through problem 12.6 in MTW which involves formulating Newtonian Gravity using Curvature as opposed to the standard formulation. This is a precursor before standard GR. In it he states that the curvature tensor in this formulation is as follows...
The Eddington Experiment famously confirmed GR by showing, as Einstein had predicted, a deflection of starlight by the Sun that was double the deflection expected by Newtonian gravity. I don't understand where Einstein's 2x number came from. I make the following assumptions:
1. That a ray of...
...y and Coulomb's law diverge as ##r\rightarrow##0? I mean, if a point light source emits light omnidirectionally, the intensity converges at the source, right?
THIS is how I should've worded my previous post!
what about Modified Newtonian Dynamics + dark matter both right and both correct
Are sterile neutrinos consistent with clusters, the CMB and MOND?
Garry W. Angus
arXiv:0805.4014 [
If no sterile neutrinos then Modified Newtonian Dynamics + primordial black holes
Primordial Black Holes...
Hi everyone! Hope your day is going well. I’m an ex-physics student who recently wanted to go back to studying the subject (as a hobby, mostly). So I picked up Zee’s GR book since GR is the thing I’m the most interested in. I expected to hit a wall on some basic things since I’m rusty, and did...
This is jut an example to illustrate my doubt. I don't know how to obtain the tracjectory given only the acceleration in this format. I realized that if i can show that there is an constat vector 'a' that satisfy a•r=constant, than the motion would be on the surface of a cone. So i tried to make...
Let's say a small object orbits around massive object at some distance in perfectly circular orbit. In Newtonian physics the force acted upon orbiting body is:
Force = m1 * orbital_speed^2 / distance = G * (m1*m2) / r^2
for an object of 1kg orbiting a body of 2*30^kg at the distance of 1.521 *...
When light is viewed from an accelerating frame of reference it appears to bend at a rate of a/c (the acceleration a being at right angles to c). By the Principle of Equivalence the bending of a beam of light in a uniform gravitational field ought to be g/c rad/sec. In principle you could use...
During lecture today, we were given the constitutive equation for the Newtonian fluids, i.e. ##T= - \pi I + 2 \mu D## where ##D=\frac{L + L^T}{2}## is the symmetric part of the velocity gradient ##L##. Dimensionally speaking, this makes sense to me: indeed the units are the one of a pressure...
We can write the Newtonian metric in the form of
$$ds^2 = -(1 - 2M/r)dt^2 + (1+2M/r)[dr^2 + r^2d\Omega^2]$$
In order to obtain the orbit equation I have written the constant of motion,
$$e = (1 - 2M/r)(\frac{dt}{d\tau})$$
and
$$l = r^2sin^2(\theta)(\frac{d\phi}{d\tau})$$
I can divide the...
Under the Lorentz Gauge the Einstein Field Equations are given as
$$G^{\alpha \beta} = -\frac{1}{2}\square \bar{h}^{\alpha \beta}$$
Then the linearized EFE becomes,
$$\square \bar{h}^{\mu\nu} = -16 \pi T^{\mu\nu}$$
For the later parts, I ll share pictures from the book
I have couple of...
[Mentor Note: thread split off from a different thread]
https://www.physicsforums.com/threads/heavier-objects-fall-faster.1002022/
Since seeing this thread yesterday, I have been trying to derive the time equation for the collision of two masses due to Newtonian gravity. Unfortunately, this...
Let's imagine an ideal scenario where you're lifting your own weight in its entirety. Let's say a woman weighing 100 lbs. Suppose she's doing an idealized handstand and pushup from that position. So she's lifting 100 lbs. Let's say ideally all of the forces are on her arms only. Do these forces...
The answer is tD = [D_0 - 3/4ct - 1/2ct] I just have 2 questions.
I realize for 2 vectors approaching it is negative for distance and for velocity positive. What be the rule for time? How do I find vector answers for velocity and distance and time?
I am confused why I have "td = ..." ? Can...
Hello. The questions are: Why Newtonian mechanics is not applicable to quantum mechanics and more natural phenomena in gravity? So, we needed general relativity which offers a metric theory about gravity and applies to more phenomena in nature, but how is this explained that special and general...
Hello there.My question is:can Newtonian gravity be generalised to include not only bodies with mass but energy also?Thank you.Can my thread be moved to classical physics?
Before I attempt to delve into the math of tensors and curved spacetime, I'm hoping to get a more general intuitive grasp of things. As such, I'm parsing through a lot of lower level articles on these topics, and several that I've come across have argued that Newtonian gravity can be thought of...
Hi, I have a question about a hanging rope - how do you find it's mass? I've been searching a long time, stumbled across some advanced calculus involving catenary functions and equations, but couldn't quite figure it out.
$$ R - f = m\ddot x$$ $$N - mg = m\ddot y$$
were N and R are the normal reactions from the smooth wall and rough ground.
and f is the friction provided by the ground.
$$ f = \mu N = cot(\phi)N/4$$
i tried to formulate a constraint relation between ##\ddot x## and ##\ddot y## so that I could...
Hi,
I was trying to derive relativistic momentum equation using classical momentum equation but it didn't work. Could you please help me? Thank you!
Where am I wrong? Or, is not possible, in any way, to derive relativistic momentum using Newtonian momentum equation? Thanks!
On p.170 of French's book on special relativity there is this thougth experiment attributed to Lewis and Tolman (1909). It is about two individuals throwing identical balls of mass M at each other with identical speed. The balls bounce against each other and are caught again.
See attached...
I was discussing a problem related to Einstein's universe model. As we all know its an unstable equilibrium. So a small fluctuation in the density would result in an either expanding or contracting universe. However, I read that
"There are static and stable solutions in Newtonian gravity...
As you can see from the very last line of my post, this whole post may come from the fact that I don't get sarcasm o0)Hi, reading the above mentioned book I ran into the following footnote:
Postulate A was earlier stated as:
An alternative, but equal, version of Postulate A is given the page...
I have been trying out with this one for a long time with no luck getting the exact expression. I am pretty sure this is somehow related to Kepler's third law but unable to establish the connection and the integrals I get from energy conservation yield different results. Any ideas?
In Newtonian mechanics, conservation laws of momentum and angular momentum for an isolated system follow from Newton's laws plus the assumption that all forces are central. This picture tells nothing about symmetries.
In contrast, in Hamiltonian mechanics, conservation laws are tightly...
Similarly the paper by @buchert and @ehlers
https://arxiv.org/abs/astro-ph/9510056
Here the author has defined ##v_{ij}=\frac{\partial v_i}{\partial x_j}=\frac{1}{2}(\frac{\partial v_i}{\partial x_j}+\frac{\partial v_j}{\partial x_i})+\frac{1}{2}((\frac{\partial v_i}{\partial...
I am writing a paper for "Dynamics and statics" course. I am really interested in Graphene. I am not if this is a good topic for this specific course. Any suggestions? Thank you in advance
Newtonian Physics states in part that 'every object has an absolute state of motion relative to absolute space, so that an object must be either in a state of absolute rest, or moving at some absolute speed.'
Granting that if absolute space were to exist, we have no means to measure it at...
Perhaps naively I assumed that for a relativistic particle the product of mass times velocity would be the same in both Newtonian and Einsteinian mechanics. The simplistic thinking was the mass increase in relativistic dynamics would balance out the non-real superluminal velocity of a particle...
I have read in several popular physics texts that general relativity predicts that gravity deflects light, but that Newtonian mechanics, in contrast, predicts that the trajectory of light is not affected by gravity. However, I am very skeptical and confused about this result.
We of course have...
Hi.
I've read that there's no Newtonian analogue of the energy-momentum relation
$$E^2-(pc)^2=(mc^2)^2\enspace .$$
Why doesn't
$$E=\frac{p^2}{2m}$$
qualify as such? There's no rest energy in Newtonian physics anyway.
In GR Mass is said to curve spacetime which is the explanation for Gravity versus Newtonian physics where it is explained as all matter attracts each other. My question is how does curved spacetime cause objects traveling at different velocities to follow different paths? If gravity was only due...
Homework Statement
The problem states that there is a father pulling a 100 lb sled with a force of 100 lb at some angle. At what angle does the father have to pull in order for the sled to accelerate at 25 ft/s^2? The coefficient of kinetic friction here is given as 0.04.
Homework Equations
F...
I have several questions about the Newtonian equation for Gravity Gm1m2/r^2. First, I want to point out this equation is only valid for point masses or when the two objects are sufficiently far apart.This is because the r squared term on bottom means that the relationship between force and...
I noticed that the Schwarzschild Radius Formula and the Escape Velocity Formula are actually identical. The Schwarzschild Radius is supposed to be one of the great equations generated from Relativity, while the Escape Velocity is something that was generated just using Newtonian gravity. All you...
Hello Everbody
In Sci Shows newest video they take about alternates to Dark Matter and one of these is Modified Newtonian dynamicse. The guy states that there were two teams one proved that it existed and the other did the the opposite.
My question is why they can't and didn't compare there...
What I've read on the Michelson/Morley experiment explains that it made the idea of the luminiferous aether seem less likely, but I don't think I've ever seen an explanation of why everyone didn't just assume that light follows normal Newtonian relativity. What I mean is this: according to...
I studied the vector analysis in Arfken and Weber's textbook : Mathematical Methods for Physicists 5th edition.
In this book they give the definition of vectors in N dimensions as the following:
The set of ##N## quantities ##V_{j}## is said to be the components of an N-dimensional vector ##V##...
Homework Statement
Find the velocity ± and the position x as functions of the time t for a particle of mass m, which starts from rest at x =0 and t =0, subject to the following force functions:
(a) Fx = F0 + Ct
(b) Fx = F0 sin Ct Ct
(c) Fx = F0e^ct
where F0 and c are positive constants...
Suppose I have a wave tank partially filled with a shear thickening Newtonian fluid (Oobleck), on top of which sits a layer of water (separated by a thin membrane to prevent mixing)
If I propagate a surface wave in the water layer how will it conduct itself at the Newtonian/Non Newtonian Fluid...
So, I have heard that the deflection of starlight using Newtonian gravity is only half of the deflection predicted by Einstein. NE1 know where I can find an example of the former calculation? thanks
Greg Bernhardt submitted a new PF Insights post
The Schwarzschild Metric: Part 3, A Newtonian Comparison
Continue reading the Original PF Insights Post.
What types of objects does Newtonian mechanics deal with? Is it just rigid bodies? I’m not sure how Newton’s laws could explain something like the motion of a wiggling rope.